Industrial boilers operate by using a heat source to create steam from water or another type of a working fluid. The steam may be used to drive a turbine or other type of load. The heat source may be a combustor that burns a fuel-air mixture therein. Heat may be transferred to the working fluid from the combustor via a heat exchanger. Burning the fuel-air mixture, however, may generate residues on the surface of the combustor, heat exchangers, and the like. Further, the working fluid flowing through the tubes of the heat exchangers and other types of enclosures also may develop residues and other deposits therein. The presence of these residues and other deposits may inhibit the efficient transfer of heat to the working fluid. This reduction in efficiency may be reflected by an increase in the exhaust gas temperature from the backend of the process as well as an increase in the fuel burn rate required to maintain steam production and energy output. Periodic removal of the residues and deposits thus may help maintain the overall system efficiency. Typically, the complete removal of the deposits generally requires the boiler or other system to be shut down while the cleaning process is performed.
Pressurized steam, water jets, acoustic waves, mechanical hammering, and other methods having been used to remove these internal deposits while offline. For example, mechanical methods may include different kinds of brushes, headers, and lances to mechanically pass through the tube. Chemical methods may include the use of different kinds of chemical solutions. Pneumatic/hydraulic methods may use compressed air or high pressure water jets. Vacuum methods also may be used. Finally, combinations of these methods also are known.
More recently, detonative combustion devices have been employed. Specifically, a pulsed detonation combustor external to the boiler, heat exchanger tubes, or other system may be used to generate a series of detonations or quasi-detonations that may be directed therein. The high speed shockwaves travel through the boiler, the tubes, or otherwise and loosen the deposits from the surfaces therein. The pulsed detonation combustor systems result in quick cleaning, however, tend to require a large footprint. Moreover, the strength/effectiveness of the shockwave decreases as it travels away from the detonation combustor such that there is a limit to the cleaning range.
There is thus a desire for cleaning systems and methods that are able to operate quickly to remove internal deposits in boilers, heat exchanger tubes, and the like so as to minimize downtime. It is further desirable that the systems and methods may operate within the existing environment, i.e., that the system is able to fit physically within the existing space restrictions while being able to reach all of the tubes or other surfaces that require cleaning with the most intense pressure wave throughout the vessel.